Multicarrier wireless networks use a plurality of individual carriers (subcarriers) for communicating data symbols. When severe interference or deep fading is present on any one of the subcarriers, the data symbol transmitted on that subcarrier may not be able to be recovered.
Interference is particularly an issue with WiFi networks because they operate in unlicensed portions of the frequency spectrum. Interferers can jam a portion of frequency band or some of the spatial channels. Furthermore, channel allocations of nearby WiFi networks may partially overlap resulting in interference in a significant portion of the bandwidth (up to ⅔ of the subcarriers). In some cases an entire packet may be lost due, regardless of how good the channel quality may be on the other subcarriers because the error-correcting (e.g., convolutional) code may not be able to tolerate loosing most or all the bits that are transmitted on the jammed subcarriers.
Thus, there are general needs for transmitters and methods of reducing the effects of interference in a wireless network. There are also general needs for transmitters and methods of reducing the effects of interference in a wireless network that provide for improved throughput and reliability against severe interference and fading.